Tracking iceberg -SMOS over AntarcticaEwa Slominska, (email:ewa@cbk.waw.pl)W. Marczewski, J. SlominskiSpace Research Center PAS

Motivation

I For nearly a year, thedrifting iceberg was trackedon the SMOS data.

I An isolated, floating alongAntarctica, set of 8-10SMOS DGG pixels is a focalpoint for this analysis. Itwas characterised by anexcess in brightnesstemperature ofapproximately 30K, whencompared to surroundingopen water.

I With a little help from the CESBIO SMOS Blog followers the iceberg was identified as the B15J(more details [4]).

I As part of a natural cycle, ice shelves periodically calve icebergs. In March 2000, Antarctica’s RossIce Shelf released a colossal berg, assigned as B-15. The B-15 was the world‘s largest recordediceberg with the area of over 11,000 km2. B-15 started to break into smaller pieces in 2002 and2003. One of the pieces from the “B-15 family” (more precisely B-15J) was spotted by the SMOSsatellite.

Figure: SMOS chases iceberg B15

Goals

I Examine the motion of spotted object.

I Examine the iceberg evolution in terms of measured by SMOS brightness temperature.

I Examine polarimetric characteristics for the DGG pixels corresponding to tracked iceberg.

Data & Methodology

1. SMOS Level 1c browse Land and Sea Data were merged in order to produce weaklyaveraged global maps for the first Stokes parameter. - This provides relevant insight into dynamicsof processes observed by SMOS. Temporal evolution of the first Stokes parameter revealed set ofseveral DGG pixels drifting from the Ross Sea eastwards. Comparison with ENVISAT imagesconfirmed that spotted object is an iceberg.

2. DGG pixels of the object floating For the of several DGG pixels

Figure ii: Path of the spotted iceberg based on the almost whole year of observations

Analysis

By merging the SMOS land and sea L1C data, we obtain global maps of the brightness temperatureat the top of the atmosphere at the L-band. This is a starting point for spatial and temporalanalysis of the first Stokes parameter variations. One-year set of weakly averaged global maps of thefirst Stokes parameter clearly revealed dynamics of seasonal changes, especially at high latitudes andin the polar regions. It shows the changes in ice extent over Antarctica, ice melting in the Arctic Seaor the Hudson Bay.Current studies are focused only on the Southern Hemisphere, mainly Antarctica and the region ofthe Ross Sea, where we were able to detect with SMOS one of the biggest icebergs ever recorded(B15J - part of the B15 iceberg). The derived iceberg motion indicated significant change ofdirection in the middle of September 2011, when the berg started to move equatorward. Strayingfrom Antarctica, was accompanied with sequential decrease of the brightness temperature. At theend of December, the signatures of observed iceberg were barely apparent, making further trackingnot feasible.It is highly probable that SMOS documented the final stage of evolution of B-15J. So apart fromthe motion track and speed, we examine the variations of the brightness temperature, as well aspolarimetric characteristics of the spotted iceberg.

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Analysis Conclusion & Work to do...

References

[1] Barre H. M.J., Duesmann B., Kerr Y.H.: The Mission and the System, IEEE TGRS, VOL. 46, No. 3, MARCH 2008

[2] Kerr Y.H., Waldteufel P., Wigneron J.-P., Delwart S., Cabot F., Boutin J., Escorihuela M.-J., Font J., Reul N., Gruhier C., Juglea S.E.,

Drinkwater M.R., Hahne A., Martin-Neira M., and Mecklenburg S.: The SMOS Mission: New Tool for Monitoring Key Elements of the

Global Water Cycle, Proceedings of the IEEE, Vol. 98, No. 5, May 2010

[3] Kerr, Y. H., P. Waldteufel, P. Richaume, P. Ferrazzoli, and J.-P. Wigneron: SMOS level 2 processor soil moisture Algorithm Theoretical

Basis Document (ATBD), Toulouse, France: CESBIO, vol. SO-TN-ESL-SM-GS-0001, V3.a, 2008.

[4] CESBIO SMOS blog - http://www.cesbio.ups-tlse.fr/SMOS_blog/?tag=icebergReferences : Acknowledgments : Contact :

Ewa SlominskaSpace Research Center PASBartycka 18A00-716 Warsaw, POLANDE-mail: ewa@cbk.waw.pl